Heretofore (see, e.g., U.S. Pat. No. 5,159,182, No. 5,338,923, No. 5,457,590, No. 5,471,038 and No. 5,584,043) others have described devices which allow digitized audio or graphics information to be interfaced to equipment that operates with magnetic storage media (e.g., floppy disks and cassettes) by converting the digital information to magnetic signals which are read or “played” by the equipment's magnetic read heads.
The present invention extends this technology in many ways such as by allowing the user of the equipment to operate the equipment's standard controls to regulate the device. Various specific exemplary embodiments of the invention include, without limitation, a device of the same general physical size and shape as a standard audio cassette tape, but which accepts digital information from any of a variety of sources—including for example: Internet transmission, a digital computer, or memory cards (especially digital memory cards)—and plays this digital information through any standard audio tape cassette player. The device operates by converting the digital representation of the sound into magnetic signals which are presented to the read/write head of the cassette player equipment. The device allows the user of the cassette player to regulate the audio playback using conventional equipment controls such as: START, STOP, REWIND, FAST REWIND, FORWARD, FAST FORWARD, etc. In an additional embodiment, the device also includes user input control buttons, a display and a headphone jack all mounted in the case of the cassette device such that they are substantially flush with the case and will not interfere with the use in a cassette player. In this embodiment the user can use the cassette device in a cassette player and also use the cassette device as a portable and free standing, digital audio player.
The exemplary embodiments described herein provide advantages over other technology which interfaces digital information through conventional magnetic read/write devices. For example, the illustrative embodiments contrast with existing CD-to-cassette adapters in a number of ways such as by: (1) being self-contained and not requiring a connection to another device outside the bounds of the playing equipment—there are no wires protruding from the equipment; (2) containing a digital processor—it is not merely a simplistic connector or “plug”; and (3) controlling the rendering (playback) through use of the equipment's normal controls—rather than the control of, say, an external CD player. The exemplary embodiments differ from other processor-based digital adapters, for example, by allowing the rendition to be controlled by the equipment's playback controls.
The invention relates to a device which accepts digital information from any of a number of different sources, converts such digital information to magnetic signals which are read by the playing equipment. These two components are often generically referred to hereinafter as the “device” and the “equipment”. The device provides for response to controls operated by the user of the playing equipment. In an additional embodiment, the user can also remove the device from the equipment and operate user controls integral to the device in a free standing manner.
In one exemplary implementation, the device has the same general physical dimensions of a standard audio cassette; at least one digital processor; and a slot into which electronic media such as, for example, memory cards, smart cards having a processor and a memory embodied thereon or media sized to be received by the device and being of the type commercially sold by Toshiba Corporation as SmartMedia, or commercially sold by SanDisk Corporation or Sony Corporation as a MultiMedia card, or Memory Stick, respectively. The device includes converter circuitry whereby digital data stored in digital memory is converted to an analog signal which is magnetically coupled to the read head of the equipment. Additionally, a transducer is embodied in the “tape” edge of a normal cassette; where the transducer presents magnetic signals to the equipment's read head, such transmissions being comparable to those which would have been detected as if magnetic media were being played. The device includes various sensors to detect changes in at least one of the tape equipment mechanisms, including, for example: the tape transport, the capstan, the hub spindle driver(s), the pinch roller, the equipment's read/write head movement, the head assembly, and the erase head.
Information detected by the sensors is presented to at least one of the device's digital processors. Software is included to permit at least one of the digital processors to use the sensor information to direct changes in the magnetic information which is presented to the equipment.
In another exemplary embodiment, the device is similar to that described above, except that instead of using memory cards as the information store, the device has sufficient extra memory to store performances which are to be rendered. The device is configured such that the device memory can be loaded with digital information from at least one source external to the device. Depending on the implementation, such loading may occur during the device's manufacture, as part of the distribution process, or after the user has possession. Furthermore such loading may occur only once, or may occur many times.
In yet another exemplary embodiment, the device provides for “recording” from the equipment, whereby the information is received by the device through the transducer from the equipment's read/write head and is deposited in the information store (e.g., the memory card). In addition, sensors in the device that detect and gather the various states of the equipment's control structure (such as the tape transport, head positioning mechanisms, and the motion of the spindle drive shafts) may be implemented in a vast variety of ways appropriate to the situation—including electrical (for example, armatures, or contact switches), electronic (for example magnetic induction, Hall-effect sensors, pressure sensitive transistors), optical (for example, using light emitting diodes (LEDs) and optical sensors), or even mechanical (for example, using gears and trip counter switches) sensors. Ultimately, signals from the sensors will be presented to the digital processor. The sensors identified above are not intended to be exhaustive as there are many other techniques and variations which those skilled in the art of designing digital or electromechanical devices may elect to apply.
In an additional implementation of the embodiment of the device having integral user controls, a display and headphone connector, the device may also include an integral microphone and/or microphone connector. In this embodiment, the user can use the device for recording on recording equipment and can also use the device as a portable, free standing, digital audio recorder. The user can use the integral microphone, plug an external microphone into the connector or plug in a patch cable connected to the “record output” of an audio amplifier.
In addition to the “information store” memory used to store, for example, a musical performance, whether this storage be removable or non-removable from the device, the device may contain additional memory. For example, a memory used by the processor for “temporary” or “transient” activities, including, depending on the embodiment, one or more storage devices used for:                processing the digital performance data: encrypting or decrypting it, change it from various encoded formats (e.g., MPEG, WAV, etc.) to those more appropriate), change it to a form suitable for the digital-to-analog converter (or, depending on the embodiment and the capabilities of the processor, performing the digital to analog conversion directly), or whatever other interpreting, processing or analysis may be required;        monitoring the recent history of the device's sensors (see the description below of clock 290), and controlling the device accordingly; and        regulating the power supply and the flow of power to and from various components of the device, including regulating the flow of power from a generator and/or battery, charging the battery, and determining when various components should receive power, including the processor itself.        
Candidates for this type of memory include volatile RAM, or static RAM, which retains its contents only while it is powered. This type of memory is currently economical, although it might involve additional consideration on the part of implementors to insure that only “scratch” information is held here, and to store information to be retained across power outages (if any) elsewhere in more “permanent” memory.
“Permanent” memory may be used by the processor to record the state of the device and the state of the playback during periods when the device is (or is subject to being) without power. Depending on the embodiment, if there is no battery, such times could occur whenever the generator is not being driven by the spindle. For example, saving the position within the performance in order to resume playback (thus mimicking a tape which can be stopped, removed, and thence resumed), and saving the state of the device, and the various components, especially if the device is powered with only a generator and no battery. In this case, the processor could frequently update the permanent memory with “state” information relevant to continuing processing after the power is resumed.
Candidates for this type of “permanent” memory include for example “E-squared” (Electrically Erasable) memory or “Flash” memory. To conserve power, the processor may elect to turn off some (or all) of the blocks of memory when they are unused. Important information could be organized to stay only a subset of the memory blocks to which power is left on.
In summary, the standard equipment, such as an analog cassette player, responds to user actions (such as by operating PLAY, REWIND, FAST FORWARD, STOP, PAUSE, etc. controls) by changing the configuration and speed of its tape transport and read head position, etc. The device has sensors to detect these changes and responds by altering the nature of the magnetic signal which is generated. These sensors can be mechanical, electrical, electronic, optical, or any combination thereof.